U.S. patent application number 15/686667 was filed with the patent office on 2018-03-01 for chemical mechanical polishing tool with robot access to cassettes.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Yongqi Hu, Thomas Lawrence Terry.
Application Number | 20180056479 15/686667 |
Document ID | / |
Family ID | 61241253 |
Filed Date | 2018-03-01 |
United States Patent
Application |
20180056479 |
Kind Code |
A1 |
Hu; Yongqi ; et al. |
March 1, 2018 |
CHEMICAL MECHANICAL POLISHING TOOL WITH ROBOT ACCESS TO
CASSETTES
Abstract
A semiconductor fabrication system includes a chemical
mechanical polishing system, a cassette holding area enclosed by a
wall and having a door openable by an operator to place one or more
cassettes into the cassette holding area, a robot configured to
transfer substrates between a cassette in the cassette holding area
to the chemical mechanical polishing system, a computer controller
configured to cause the robot to move to a home position, a circuit
breaker in a power supply line to the robot, a door sensor to
detect whether the door is open, a robot presence sensor to detect
whether the robot is in the home position, and control circuitry
configured to receive signals from the door sensor and the robot
presence sensor and cause the circuit breaker to cut power to the
robot if the door is open and the robot is not in the home
position.
Inventors: |
Hu; Yongqi; (Fremont,
CA) ; Terry; Thomas Lawrence; (Hollister,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
61241253 |
Appl. No.: |
15/686667 |
Filed: |
August 25, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62380273 |
Aug 26, 2016 |
|
|
|
62464204 |
Feb 27, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G05B 19/19 20130101;
H01L 21/30625 20130101; H01L 21/67778 20130101; B24B 27/0069
20130101; B24B 49/12 20130101; H01L 21/67766 20130101; B24B 41/02
20130101; H01L 21/67219 20130101; B24B 41/005 20130101; H01L
21/67769 20130101; B24B 37/345 20130101; H01L 21/67092 20130101;
H01L 21/68707 20130101; H01L 21/67772 20130101; B24B 37/005
20130101; H01L 21/67075 20130101; H01L 21/67259 20130101; G05B
2219/31276 20130101 |
International
Class: |
B24B 37/34 20060101
B24B037/34; H01L 21/677 20060101 H01L021/677; H01L 21/687 20060101
H01L021/687; H01L 21/67 20060101 H01L021/67; G05B 19/19 20060101
G05B019/19 |
Claims
1. A semiconductor fabrication system, comprising: a chemical
mechanical polishing system; a cassette holding area enclosed by a
wall and having a door openable by an operator to place one or more
cassettes into the cassette holding area; a robot configured to
transfer substrates between a cassette in the cassette holding area
and the chemical mechanical polishing system; a computer controller
configured to cause the robot to move to a home position; a circuit
breaker in a power supply line to the robot; a door sensor to
detect whether the door is open; a robot presence sensor to detect
whether the robot is in the home position; and control circuitry
configured to receive signals from the door sensor and the robot
presence sensor and cause the circuit breaker to cut power to the
robot if the door is open and the robot is not in the home
position.
2. The system of claim 1, wherein the robot presence sensor
comprises a beam emitter configured to direct a light beam through
a location where a portion of the robot is supposed to be when the
robot is in the home position, and a detector positioned to receive
the beam when the beam is not being blocked by the robot.
3. The system of claim 2, wherein the beam emitter is configured to
direct the light beam through a location where an arm of the robot
is supposed to be when the robot is in the home position.
4. The system of claim 2, wherein the beam emitter is configured to
direct the light beam through a location where an end effector of
the robot is supposed to be when the robot is in the home
position.
5. The system of claim 2, wherein the robot presence sensor
comprises a first sensor to detect motion of an arm of the robot
and a second sensor to detect motion of an end effector of the
robot.
6. The system of claim 5, wherein the first sensor comprises a
first beam emitter configured to direct a first light beam through
a location where the arm of the robot is supposed to be when the
robot is in the home position, and a first detector positioned to
receive the first light beam when the beam is not being blocked by
the arm, and the second sensor comprises a second beam emitter
configured to direct a second light beam through a location where
the end effector of the robot is supposed to be when the robot is
in the home position, and a second detector positioned to receive
the second light beam when the beam is not being blocked by the end
effector.
7. The system of claim 1, wherein the cassette holding area
comprises a cassette loading area and a cassette staging area, and
wherein the robot is configured to transfer the cassette between
the loading area and the staging area.
8. The system of claim 7, wherein the home position is in the
staging area.
9. The system of claim 8, wherein a wall has aperture connecting
the cassette loading area and the cassette staging area, and the
home position is adjacent the aperture.
10. The system of claim 7, wherein the door is located in the
loading area.
11. The system of claim 7, wherein the robot is configured to
remove a substrate from the cassette in the staging area and place
the substrate in a transfer station in the chemical mechanical
polishing system.
12. The system of claim 11, wherein the robot is configured to
retrieve the substrate from the transfer station in the chemical
mechanical polishing system and return the substrate to a cassette
in the staging area.
13. The system of claim 1, comprising a wall between the cassette
holding area and the chemical mechanical polishing system, and a
port in the wall for transfer of substrates between the cassette
holding area and the chemical mechanical polishing system by the
robot.
14. The system of claim 13, wherein the home position is adjacent
the port.
15. The system of claim 1, wherein the control circuitry is
hardwired.
16. The system of claim 1, wherein the control circuitry comprises
a manually operated power restore switch to cause the circuit
breaker to restore power to the robot.
17. A method of operating a semiconductor fabrication system,
comprising: transferring substrates from a cassette holding area to
a chemical mechanical polishing system with a robot; opening a door
to the cassette holding area and loading a cassette having
substrates into the cassette holding area; detecting whether the
door is open; detecting whether the robot is in a home position;
and in response to detecting that the door is open and that the
robot is not in the home position, cutting power to the robot.
18. The method of claim 17, wherein detecting whether the robot is
in the home position comprises directing a light beam through a
location where a portion of the robot is supposed to be when the
robot is in the home position.
19. The method of claim 18, wherein detecting whether the robot is
in the home position comprises directing a first light beam through
a location where an arm of the robot is supposed to be when the
robot is in the home position, and directing a second light beam
through a location where an end effector of the robot is supposed
to be when the robot is in the home position.
20. The method of claim 17, comprising transferring the cassette
from a cassette staging area to a cassette loading area with the
robot, and removing a substrate from the cassette in the staging
area and placing the substrate in a transfer station in the
chemical mechanical polishing system with the robot.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Application Ser.
No. 62/380,273, filed on Aug. 26, 2016, and claims priority to U.S.
Application Ser. No. 62/464,204, filed Feb. 27, 2017, the entire
disclosures of which are incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to chemical mechanical
polishing, and in particular to controlling a robot that accesses
cassettes in a chemical mechanical polishing tool.
BACKGROUND
[0003] An integrated circuit is typically formed on a substrate by
the sequential deposition of conductive, semiconductive, or
insulative layers on a silicon wafer. A variety of fabrication
processes require planarization of a layer on the substrate. For
example, one fabrication step involves depositing a conductive
filler layer on a patterned insulative layer to fill the trenches
or holes in the insulative layer. The filler layer is then polished
until the raised pattern of the insulative layer is exposed. After
planarization, the portions of the conductive filler layer
remaining between the raised pattern of the insulative layer form
vias, plugs and lines that provide conductive paths between thin
film circuits on the substrate. Another fabrication step involves
planarization of an insulative layer until it reaches a target
thickness over an underlying layer.
[0004] Chemical mechanical polishing (CMP) is one accepted method
of planarization. A chemical mechanical polishing system typically
includes a carrier head to hold the substrate against a rotating
polishing pad. The carrier head provides a controllable load on the
substrate to push it against the polishing pad. A polishing liquid,
such as slurry with abrasive particles, is supplied to the surface
of the polishing pad.
[0005] To transfer the substrates to the chemical mechanical
polishing system, the substrates are typically loaded into a
cassette, e.g., manually or at a previous processing station. This
cassette can then be carried and placed into a factory interface
module, which is typically an area accessible to the cleanroom
environment of the semiconductor manufacturing facility. A robot
can transfer a substrate from a cassette in the factory interface
module to a load/unload station in the CMP tool, where the
substrate can be loaded into or unloaded from the carrier head.
SUMMARY
[0006] In one aspect, a semiconductor fabrication system includes a
chemical mechanical polishing system, a cassette holding area
enclosed by a wall and having a door openable by an operator to
place one or more cassettes into the cassette holding area, a robot
configured to transfer substrates between a cassette in the
cassette holding area to the chemical mechanical polishing system,
a computer controller configured to cause the robot to move to a
home position, a circuit breaker in a power supply line to the
robot, a door sensor to detect whether the door is open, a robot
presence sensor to detect whether the robot is in the home
position, and control circuitry configured to receive signals from
the door sensor and the robot presence sensor and cause the circuit
breaker to cut power to the robot if the door is open and the robot
is not in the home position.
[0007] In another aspect, a method of operating a semiconductor
fabrication system includes transferring substrates from a cassette
loading area to a chemical mechanical polishing system with a
robot, opening a door to the cassette loading area and loading a
cassette having substrates into the cassette holding area,
detecting whether the door is open, detecting whether the robot is
in a home position, and in response to detecting that the door is
open and that the robot is not in the home position, cutting power
to the robot.
[0008] Certain implementations can include one or more of the
following advantages. The robot can be prevented from moving away
from a home position when a door to the factory interface module is
open. Safety of the human operator can be maintained, while the
downtime of the system can be reduced.
[0009] The details of one or more implementations are set forth in
the accompanying drawings and the description below. Other aspects,
features and advantages will be apparent from the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a schematic perspective view of a processing
system that includes a chemical mechanical polishing system.
[0011] FIG. 2 is schematic top view of a processing system that
includes a chemical mechanical polishing system.
[0012] FIG. 3 is a schematic side view of a robot in a home
position.
[0013] FIG. 4 is a schematic block diagram of a robot
interlock.
[0014] FIG. 5 is a flow chart illustrating operation of the robot
interlock.
[0015] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0016] In order to protect the operator, it is important that the
robot be immobilized when cassettes are to be loaded or unloaded in
a chemical mechanical polishing system. One technique to accomplish
this is to have a switch on the doors, with the switch connected to
the robot's contactors (effectively a circuit breaker for the
robot) such that power is cut to the robot when the door is opened.
Completely cutting power to the robot may be required by various
state or national occupational safety regulations. Unfortunately,
once power is cut to the robot, restarting the robot after the
doors are closed can require complete re-initialization of the
robot, which can be time-consuming (e.g., more than 80 seconds),
reducing throughput.
[0017] By placing a sensor system in the cassette holding area that
will trigger the robot contactors when the robot moves from a home
position, operator safety can be maintained while permitting the
doors to be opened without requiring re-initialization of the
robot.
[0018] Referring to FIG. 1, a substrate processing system 10
includes a chemical mechanical polishing system 20 located adjacent
to a substrate loading apparatus 30. The substrate loading
apparatus 30 includes a cassette holding area 100 enclosed by a
wall 102, which can be transparent. A door 104 is located in the
wall 102 to permit access by the operator of the facility to a
cassette holding area 100 (see FIG. 1), which can include a
cassette loading area 32 and/or a cassette staging area 33 (see
FIG. 2). The wall 102 can enclose the cassette loading area 32 (see
FIG. 2). An aperture 103 (see FIGS. 1 and 3) can provide access
between the cassette loading area 32 and the cassette staging area
33.
[0019] The substrate loading apparatus 30 also includes a robot
110, e.g., a wet robot, to transfer substrates between cassettes in
the holding area 100, e.g., in the cassette staging area 33, to the
chemical mechanical polishing system 20. The robot 110 can also be
used to transfer cassettes between the loading area 32 and the
staging area 33.
[0020] Substrates 40 are transported to the substrate processing
system 10 in one or more cassettes 42. An operator opens the door
104, places the cassette 42 in the loading area 32, e.g., on
support, and then closes the door 104. The robot 110 then transfers
the cassette 42 from the loading area 32 to the staging area 33.
Alternatively, if the door 104 leads directly to the staging area
33, then the operator can place the cassette 42 directly into the
staging area 33.
[0021] One or more substrates 40 are then extracted from the
cassette 42 in the staging area 33 and loaded into the chemical
mechanical polishing system 20 by the robot 110. The polishing
system 20 then polishes the substrates 40, and the robot 110 then
returns the substrates 40 to either the original cassette 42 or a
different cassette in the staging area 33. Once the desired
polishing operations are completed for substrates in the cassette
42, the robot can transfer the cassette 42 back to the loading area
32, and the operator can open the door 104 and remove the cassette
42 and then close the door (or for some positions of the door, the
operator could remove the cassette directly from the staging area
33).
[0022] The operations of the substrate processing system 10, such
as motion of the robot 110, can be coordinated by controller 90,
which may include one or more programmable digital computers
executing control software. For example, the controller 90 can
include a CPU 92, memory 94 to store the software, and other
support circuits 96, e.g., input/output devices, storage devices,
etc.
[0023] The chemical mechanical polishing system 20 can be a
Mirra.RTM. chemical mechanical polisher manufactured by Applied
Materials, Inc. of Santa Clara, Calif. A description of a polisher
may be found in U.S. Pat. No. 5,738,574.
[0024] The polishing system 20 can include a lower machine base 22
with a table top 23 mounted thereon and a removable upper outer
cover 24. The machine base can support a series of polishing
stations (two stations 50a and 50c are visible) and a transfer
station 70. The polishing system 20 can also include one or more
carrier heads 82 (see FIG. 3) suspended from a carrier head
transport mechanism 80, such as a rotatable carousel. Each
polishing station includes a rotatable platen on which is placed a
polishing pad, and an associated pad conditioner apparatus 60 to
maintain the polishing pad in an abraded condition.
[0025] The transfer station 70 serves multiple functions of
receiving individual substrates 40 from the loading apparatus 30
via the robot 110, loading the substrate 40 to the carrier heads,
receiving the substrates 40 back from the carrier heads, and
finally transferring the substrates back to the robot 110 to be
carried back to the loading apparatus 30. The transfer station 70
can also possibly rinse or wash the substrates, before and/or after
the polishing operation.
[0026] A wall 106 (see FIG. 2) can be interposed between the
polishing apparatus 20 and the wafer loading apparatus 30 so as to
contain slurry and other polishing debris within the polishing
apparatus 20 and away from the cassette holding area 100. A port
108 (see FIG. 2), such as an opening or sliding door, can be
located in the wall 106 for the transfer of substrates by the robot
110 between the polishing system 20 and the loading apparatus 30.
The wall 106 may act as the barrier between the clean room
containing the wafer loading apparatus 30 and a dirtier area
containing the polishing apparatus 20.
[0027] In some implementations, the cassette staging area 33
includes a holding tub 36 filled with a liquid bath 38, such as
deionized water, to receive the cassettes 42. The bath can be
sufficiently deep that the cassettes 42 and the wafers 40 contained
therein are submersed. Alternatively, the cassettes 42 can simply
be placed on a support, such as stand or shelf, or on the floor, in
the cassette staging area 33.
[0028] The robot 110 can include an extensible arm 112 descending
pending from an overhead track 114. The lower end of the arm 112 of
the robot 110 can include a wrist assembly 116 including both a
wafer blade 118 and/or a cassette claw 119. If the cassette loading
area 32 is used, then the cassette claw 119 can be operated to move
cassettes 42 between the loading area 32 and the staging area 33.
The wafer blade 118 can be operated to move substrates 40 between
the cassettes 42 in the cassette staging area 33 and the transfer
station 70.
[0029] Although FIG. 1 and the remaining figures show the loading
area 32 disposed on a side of the machine base 22 away from the
transfer station 70, this illustration is merely schematic, and
other configurations are possible. In addition, other components,
such as a wafer cleaner, a wafer drier, a metrology station, and
the like can be integrated into the substrate processing system
10.
[0030] Referring to FIG. 2, the controller 90 can be configured to
cause the descending arm 112 of the robot 110 to return to a home
position 34, e.g., when not otherwise moving substrates between the
cassettes 42 and the transfer station 70, or upon command by a
user. The home position can be in the cassette staging area 33,
e.g., adjacent to the door 108 to the chemical mechanical polishing
system 20.
[0031] The processing system 10 also includes a robot interlock 120
(see FIG. 4) to prevent the robot 110 from moving while the door
104 to cassette holding area 100 is open, but without cutting power
to the robot 110 when the robot is in the holding position 34. This
can maintain operator safety while permitting the door 104 to be
opened without requiring re-initialization of the robot 110.
[0032] Referring to FIG. 4, power for the robot 110 is directed
from a power supply 122 through a contactor 124, e.g., a circuit
breaker, to the robot. The contactor 124 can be tripped (so that
the power to the robot 110 is cut off) by control circuitry 126
that is coupled to several sensors. The contactor 124 can be
configured such that once tripped, it needs to be manually
"flipped" to restore power to the robot 110.
[0033] Referring to FIG. 2, the door 104 includes a switch 105 that
generates a signal indicating whether the door 104 is open or
closed.
[0034] In addition, referring to FIG. 3, the robot interlock 120
includes one or more robot presence sensors to detect whether the
robot 110 is in the home position 34. In some implementations, the
robot interlock includes a first sensor 130 to detect motion of the
arm 112 and a second sensor 140 to detect motion of the robot end
effector, i.e., the wafer blade 118 or cassette claw 119.
[0035] As an example, the first sensor 130 can include a
through-beam sensor that includes a first beam emitter 132, e.g.,
an LED, and a first detector 134, e.g., a photodetector. The first
beam emitter 132 is configured to generate a light beam 136 (which
could be visible or non-visible light) that passes through position
where the arm 112 is supposed to be located when the robot 110 is
in the home position. The first detector 134 is positioned to
receive the beam when the beam is not being blocked by the arm 112.
Thus, if the first detector 134 detects the light beam 136, this
indicates that the arm 112 is not in the holding position.
[0036] Similarly, the first sensor 130 can include a through-beam
sensor that includes a second beam emitter 142, e.g., an LED, and a
second detector 144, e.g., a photodetector. The second beam emitter
142 is configured to generate a light beam 146 (which could be
visible or non-visible light) that passes through position where
the end effector, e.g., the wafer blade 118, is supposed to be
located when the robot 110 is in the home position. The second
detector 144 is positioned to receive the beam when the beam is not
being blocked by the arm 112, e.g., by the end effector. Thus, if
the second detector 144 detects the light beam 146, this indicates
that the arm 112, e.g., the end effector, is not in the home
position.
[0037] Referring to FIG. 5, the control circuitry 126 operates as
follows. If the signal from the door sensor 105 indicates that the
door 104 is closed, then power to the robot can be maintained,
regardless of the signals from the one or more sensors 130, 140. On
the other hand, if the signal from the door sensor 105 indicates
that the door 104 is open, and either sensor 130, 140 indicates
that the robot 110 has moved from the home position 105, then the
control circuitry 126 trips the contactor 124, and power is cut
from the robot 110. This can require re-initialization of the robot
before further operations can be performed. However, if the signal
from the door sensor 105 indicates that the door 104 is open, but
both sensors 130, 140 indicate that the robot 110 is in the home
position, then power to the robot is maintained. This permits the
door 104 to be opened so that cassettes 42 can be loaded into the
cassette holding area 100, without cutting power to the robot 110,
thus avoiding downtime of the robot and increasing throughput of
the apparatus while maintaining operator safety. The control
circuitry 126, sensors 105, 130 and 140 can all be hardwired, e.g.,
with analog circuitry, such that the power cut-off cannot be
disabled by software.
[0038] The control circuitry 126 can include a manual power
shut-off switch (e.g., a button) in the event that the operator
needs to manually shut off power to the robot. The control
circuitry 126 can also include a manually operated power restore
switch, e.g., a button, for the operator to "flip" the contactor
124 to restore power to the robot 110, whether after a manual power
shut off or an automatic power shut off as described above when the
robot is not in the home position and the door is open.
[0039] The functional operations of the controller 90 can be
implemented through digital electronic circuitry, or in computer
software, firmware, or hardware, including the structural means
disclosed in this specification and structural equivalents thereof,
or in combinations of them.
[0040] The functional operations of the controller 90 can be
implemented through one or more computer program products, i.e.,
one or more computer programs tangibly embodied in an information
carrier, e.g., in a non-transitory machine-readable storage medium
or in a propagated signal, for execution by, or to control the
operation of, data processing apparatus, e.g., a programmable
processor, a computer, or multiple processors or computers. A
computer program (also known as a program, software, software
application, or code) can be written in any form of programming
language, including compiled or interpreted languages, and it can
be deployed in any form, including as a stand-alone program or as a
module, component, subroutine, or other unit suitable for use in a
computing environment. A computer program does not necessarily
correspond to a file. A program can be stored in a portion of a
file that holds other programs or data, in a single file dedicated
to the program in question, or in multiple coordinated files (e.g.,
files that store one or more modules, sub-programs, or portions of
code). A computer program can be deployed to be executed on one
computer or on multiple computers at one site or distributed across
multiple sites and interconnected by a communication network.
[0041] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *